the Poseidonians in the Tyrrhenian
Gulf, who although of Greek origin, became barbarized as
Tyrrhenians or Romans and changed their speech and the
customs of their ancestors. But they observe one Greek
festival even to this day; during this they gather together
and call up from memory their ancient names and customs,
and then, lamenting loudly to each other and weeping,
they go away.

Athenaios, Deipnosophistai, Book 14, 31A (632)
The Poseidonians forgot the Greek language
after so many centuries of mingling
with Tyrrhenians, Latins, and other foreigners.
The only thing surviving from their ancestors
was a Greek festival, with beautiful rites,
with lyres and flutes, contests and garlands.
And it was their habit towards the festival's end
to tell each other about their ancient customs
and once again to speak Greek names
that hardly any of them still recognized.
And so their festival always had a melancholy ending
because they remebered that they too were Greeks,
they too once upon a time were citizens of Magna Graecia.
But how they'd fallen now, how they'd changed,
living and speaking like barbarians,
cut off so disastrously from the Greek way of life.